SEMINAR ON IPv4SEMINAR ON IPv4

By Inder GulatiBy Inder Gulati

ContentsContents What is IP Address. What is IP Address. IP History and Management.IP History and Management. Classes of IP Addresses.Classes of IP Addresses. Valid and Invalid IP.Valid and Invalid IP. Subnet Mask.Subnet Mask. What is Subnetting.What is Subnetting. Types of SubnettingTypes of Subnetting - FLSM (Full Length Subnet Mask)- FLSM (Full Length Subnet Mask) - VLSM (Variable Length Subnet Mask)- VLSM (Variable Length Subnet Mask) Supernetting.Supernetting.

What is an IP Address?What is an IP Address?

An An Internet Protocol (IP) Internet Protocol (IP) address address is a number that is a number that identifies a device on a identifies a device on a

computer network.computer network.

IP HISTORY AND IP HISTORY AND MANAGEMENTMANAGEMENT

The early years: 1981 – 1992The early years: 1981 – 1992

The boom years: 1992 – 2001The boom years: 1992 – 2001

“It has become clear that … these problems are likely to become critical within the next one to three years.” (RFC1366)

“…it is [now] desirable to consider delegating the registration function to an organization in each of those geographic areas.” (RFC 1338)

1992:

Recent years: 2002 – 2009Recent years: 2002 – 2009

2004:

Establishment of the Number Resource Organisation

User

Assignment

ISP

Allocation

RIR*Allocation

IANAIP

Address Management TodayAddress Management Today

IETF

RIR : Representative of ISPRIR : Representative of ISP

RIR (Regional Internet RegistriesRIR (Regional Internet Registries A A regional Internet registryregional Internet registry ( (RIRRIR) is an organization overseeing the ) is an organization overseeing the

allocation and registration of Internet Number resources within a particular allocation and registration of Internet Number resources within a particular region of the world. Resources include IP addresses. region of the world. Resources include IP addresses.

There are currently five RIRs in operation:There are currently five RIRs in operation:

American Registry for Internet NumbersAmerican Registry for Internet Numbers (ARIN) for North America and (ARIN) for North America and parts of the Caribbean parts of the Caribbean

RIPE Network Coordination CentreRIPE Network Coordination Centre (RIPE NCC) for (RIPE NCC) for EuropeEurope, the , the Middle EastMiddle East and and Central AsiaCentral Asia

Asia-Pacific Network Information Centre (APNIC) for Asia and the Asia-Pacific Network Information Centre (APNIC) for Asia and the Pacific region Pacific region

Latin American and Caribbean Internet Addresses Registry (LACNIC) for Latin American and Caribbean Internet Addresses Registry (LACNIC) for Latin America and parts of the Caribbean region Latin America and parts of the Caribbean region

African Network Information Centre (AfriNIC) for Africa African Network Information Centre (AfriNIC) for Africa

Classes of IP AddressesClasses of IP AddressesClassesClasses RangeRange BinaryBinary Total number Total number

of networksof networksTotal number of Total number of hosthost

Class AClass A 0.0.0.0 - 127.255.255.2550.0.0.0 - 127.255.255.255 0xxxxxxx xxxxxxxx 0xxxxxxx xxxxxxxx xxxxxxxx xxxxxxxxxxxxxxxx xxxxxxxx 128128 1677721616777216

Class BClass B 128.0.0.0 - 191.255.255.255128.0.0.0 - 191.255.255.255 10xxxxxx xxxxxxxx 10xxxxxx xxxxxxxx xxxxxxxx xxxxxxxxxxxxxxxx xxxxxxxx 1638416384 6553665536

Class CClass C 192.0.0.0 -223.255.255.255192.0.0.0 -223.255.255.255 110xxxxx xxxxxxxx110xxxxx xxxxxxxx

xxxxxxxx xxxxxxxxxxxxxxxx xxxxxxxx20971522097152 256256

Class DClass D 224.0.0.0 - 239.255.255.255224.0.0.0 - 239.255.255.255 1110xxxx xxxxxxxx1110xxxx xxxxxxxx

xxxxxxxx xxxxxxxxxxxxxxxx xxxxxxxxReserved for Reserved for MulticastingMulticasting

Reserved for Reserved for MulticastingMulticasting

Class EClass E 240.0.0.0 - 255.255.255.255240.0.0.0 - 255.255.255.255 1111xxxx xxxxxxxx1111xxxx xxxxxxxx

xxxxxxxx xxxxxxxxxxxxxxxx xxxxxxxxReserved for Reserved for Research and Research and Development Development

Reserved for Reserved for Research and Research and Development Development

Subnet MaskSubnet Mask

A subnet mask separates the IP address into A subnet mask separates the IP address into the network and host addresses.the network and host addresses.

Subnetting further divides the host part of an Subnetting further divides the host part of an IP address into a subnet and host address.IP address into a subnet and host address.

It is called a subnet mask because it is used to It is called a subnet mask because it is used to identify network address of an IP address by identify network address of an IP address by perfoming bitwise AND operation on the perfoming bitwise AND operation on the netmask. netmask.

Subnet MaskSubnet Mask

A process that extracts the address of the physical network A process that extracts the address of the physical network (network/subnetwork portion) from an IP address(network/subnetwork portion) from an IP address

Valid and Invalid IPValid and Invalid IP When all the HOSTID portion bits of an IP address are zero’s then it is called Network Address. When all the HOSTID portion bits of an IP address are zero’s then it is called Network Address.

class A 10.0.0.0class A 10.0.0.0 class B 172.16.0.0class B 172.16.0.0 class C 192.168.10.0class C 192.168.10.0

When all the HOSTID portion bits of an IP address are one’s then it is called Broadcast Address. When all the HOSTID portion bits of an IP address are one’s then it is called Broadcast Address.

class A 10.255.255.255class A 10.255.255.255 class B 172.16.255.255class B 172.16.255.255 class C 192.168.10.255 class C 192.168.10.255

When all the NETID as well as HOSTID portion bits of an IP address are 0’s then it is used for Default Routing (CISCO When all the NETID as well as HOSTID portion bits of an IP address are 0’s then it is used for Default Routing (CISCO Routers) Routers)

Address 0.0.0.0Address 0.0.0.0

Loopback Addresses (Self Testing)Loopback Addresses (Self Testing)

Address 127.0.0.1 (Recommended) Address 127.0.0.1 (Recommended)

??

11000000 11000000 00110010011001 1100000111000001 1111111011111110 0000000100000001

SubnettingSubnetting

Subnetting : A network is divided into several Subnetting : A network is divided into several smaller networks with each subnetwork (or smaller networks with each subnetwork (or subnet) having its subnet) having its subnetwork addresssubnetwork address

Reasons:-Reasons:- Provides addressing flexibility for the network administrator. Provides addressing flexibility for the network administrator.

--Each LAN must have its own network or subnetwork Each LAN must have its own network or subnetwork address.address.

Provides some security since access to other subnets is only Provides some security since access to other subnets is only

available through the services of a router.available through the services of a router. Reduce the Wastage of IP AddressesReduce the Wastage of IP Addresses Reduce network trafficReduce network traffic

SubnettingSubnetting Class A, B, C in IP addressing are designed with two levels of hierarchy (not Class A, B, C in IP addressing are designed with two levels of hierarchy (not

subnetted)subnetted)

-Netid and Hostid -Netid and Hostid

Subnetting (cont’d)Subnetting (cont’d) Further division of a network into smaller networks called subnetworksFurther division of a network into smaller networks called subnetworks R1 differentiating subnetsR1 differentiating subnets

Subnetting (cont’d)Subnetting (cont’d) Three levels of hierarchy : netid, subnetid, and hostidThree levels of hierarchy : netid, subnetid, and hostid

SubnettingSubnetting (cont’d) (cont’d) Three steps of the routing for an IP datagram Three steps of the routing for an IP datagram

Delivery to the site, delivery to the subnetwork, and delivery to the Delivery to the site, delivery to the subnetwork, and delivery to the hosthost

Hierarchy concept in a telephone numberHierarchy concept in a telephone number

Types of SubnettingTypes of Subnetting

IP SUBNET ZERO OR FLSM (FULL IP SUBNET ZERO OR FLSM (FULL LENGTH SUBNET MASK)LENGTH SUBNET MASK)

VLSM (VARIABLE LENGTH SUBNET VLSM (VARIABLE LENGTH SUBNET MASK)MASK)

IP-SUBNET ZERO OR FLSMIP-SUBNET ZERO OR FLSM Subnetting is based up on NETID portion bits.Subnetting is based up on NETID portion bits. In this case we need to borrow some bits from Host ID portion that depends up on the number In this case we need to borrow some bits from Host ID portion that depends up on the number

of subnetsof subnets For e.g 192.168.10.0/26For e.g 192.168.10.0/26

Step 1Step 1: Identify the total number of subnets (how many)?: Identify the total number of subnets (how many)? 22nn = number of subnets = number of subnets 2222 = 4 = 4Where n are the number of borrowed bits from hostId portion.Where n are the number of borrowed bits from hostId portion. Step 2Step 2: Identify the the total number of hosts for each subnets (how many)? : Identify the the total number of hosts for each subnets (how many)? 22m m - 2 = number of valid hosts - 2 = number of valid hosts 2266 – 2 = 62 – 2 = 62Where m are remaining number of bits in hostid portion.Where m are remaining number of bits in hostid portion.

Step 3Step 3: Calculate Subnet Mask and Range.: Calculate Subnet Mask and Range. 11111111 11111111 11111111 1100000011111111 11111111 11111111 11000000 255 .255 .255 .192255 .255 .255 .192 Range:256 - 192 = 64Range:256 - 192 = 64

Step 4Step 4: Identify the total number of subnets (Which one)?: Identify the total number of subnets (Which one)? (i) 192.168.10.0(i) 192.168.10.0 (ii) 192.168.10.64(ii) 192.168.10.64 (iii) 192.168.10.128(iii) 192.168.10.128 (iv) 192.168.10.192(iv) 192.168.10.192Step 5:Step 5: Identify the valid number of host for each subnet (which one)? Identify the valid number of host for each subnet (which one)? (i) 192.168.10.1 -- 192.168.10.62(i) 192.168.10.1 -- 192.168.10.62 (ii) 192.168.10.65 -- 192.168.10.126(ii) 192.168.10.65 -- 192.168.10.126 (iii)192.168.10.129 -- 192.168.10.190(iii)192.168.10.129 -- 192.168.10.190 (iv) 192.168.10.193 -- 192.168.10.254 (iv) 192.168.10.193 -- 192.168.10.254 Step 6Step 6:Identify the broadcast address for each subnet?:Identify the broadcast address for each subnet? (i) 192.168.10.63(i) 192.168.10.63 (ii) 192.168.10.127(ii) 192.168.10.127 (iii)192.168.10.191 (iii)192.168.10.191 (iv)192.168.10.255 (iv)192.168.10.255

VLSMVLSM

Subnetting is based up HostId portion bits.Subnetting is based up HostId portion bits.

In this case we reserve some bits in hostid In this case we reserve some bits in hostid portion rest of the bits will be in Netid portion portion rest of the bits will be in Netid portion bits.bits.

Subnet Mask vary for each subnet.Subnet Mask vary for each subnet.

VLSMVLSM

Need 10 addresses /28. Give them 16.

Need 200 addresses /24. Give them 256.

Need 500 addresses /23. Give them 512.

Need 1000 addresses /22. Give them 1024.

Need 4000 addresses /20. Give them 4096.

Before Before VLSMVLSM

Need 10 addresses Class C. Give them 256.

Need 200 addresses Class C. Give them 256.

Need 500 addresses Class B. Give them 65,536.

Need 1000 addresses Class B. Give them 65,536.

Need 4000 addresses Class B. Give them 65,536.

SupernettingSupernettingIt’s a technique that combines the multiple It’s a technique that combines the multiple subnets of same network in to one network subnets of same network in to one network

that network is known as supernetwork.that network is known as supernetwork.

SupernettingSupernetting

201.1.0.0/22

201.1.4.0/23

201.1.6.0/24

201.1.7.0/24

Advertise?

SupernettingSupernetting

201.1.0.0/22201.1.0.0/22 201.1.4.0/23201.1.4.0/23 201.1.6.0/24201.1.6.0/24 201.1.7.0/24201.1.7.0/24

Same Difference starts here

Octet 3 in binary

00000000000001000000011000000111

Same Difference starts here

21 bits the same so use /21 for summary

Any Question?Any Question?

ThanksThanks